Semiconductive device performance is determined by a variety of factors. One factor of importance is the uniformity of films deposited on a substrate. It is desirable to deposit films uniformly such that thickness variation is minimized across the surface of the substrate. For example, it may be desirable to form films having thickness variation of less than about 5% across the surface of the substrate.
However, film uniformity may be adversely affected by several factors, including heater temperature, chamber geometry, process gas flow non-uniformity, and plasma non-uniformity, among others. These factors may result in the deposition of non-uniform films on the surface of the substrate, which may ultimately reduce device performance.
Rotating the substrate during processing provides improved uniformity. However, rotating the substrate during processing requires expensive equipment, such as slip rings and rotary unions.
Therefore, there is a need for an improved apparatus and method for film uniformity in semiconductor processing.